1. Field of the Invention
The present invention relates to a liquid discharge head base material that is used in a liquid discharge head discharging a liquid.
2. Description of the Related Art
As a typical example of liquid discharge heads for discharging liquids, it is known an ink-jet recording system that conducts image recording by discharging an ink from a discharge port as droplets using energy generated by an energy-generating element and making the ink adhere to a recording medium such as paper.
U.S. Patent Publication No. 2008/0165222 discloses the following method of producing an ink-jet recording head base material.
In this method, a hollow is formed in a base material by digging the base material from the back surface of a silicon base material that is provided with an energy-generating element on its front surface side, an insulating film is formed over the entire inner wall of the hollow, and a through electrode that passes through the base material and is electrically connected to the element is formed in the hollow so as to be in contact with the film. The through electrode and the silicon base material are insulated from each other with the insulating film. Furthermore, in the method, an etching mask is formed from a resist by a photolithography technique, and an opening for accessing the through electrode to the front surface side of the base material is formed by removing the insulating film only at a portion corresponding to the bottom of the hollow.
However, when the aspect ratio of the hollow to which the through electrode is provided is large (the ratio of the depth to the diameter is large), it is thought that it is difficult to form an etching resist at high precision by processing a resist in the hollow by photolithography. When the resist is not processed at high precision, an insulating film may not have a desired shape, and a liquid discharge head may not be provided with desired electric characteristics.